Use promotion extensions to attract customers that are searching for special offers and sales relevant to your business. Holidays or special events such as Back-to-school sales and Black Friday are great times to use promotion extensions.
Use promotion extensions to include monetary or percent discounts for your products or services. You can also include any requirements needed for your promotion such as coupon or discount codes for a specified time period or a spending limit.
You can add promotion extensions at the account, campaign, or ad group level. If you create promotion extensions at different levels (account, campaign, or ad group), the most specific will be used.
Promotion extensions are free to add—you’re only charged for clicks from people viewing your ad. The cost of a click on a promotion extension equals the cost of a click on the headline in the same ad. In other words, you’ll be charged the same amount no matter which link in the same ad someone clicks. Promotion extensions offer more opportunities for your customers to click on and within your ad, but you won’t be charged for more than two clicks per ad impression. However, if someone quickly clicks on more than one link while viewing an ad, this gets treated as a second click and you won’t get charged.